All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The sin of taking such photos during that time is pardoned upon embracing Islam because Islam erases any sins committed before it, as stated by the Prophet, sallallaahu ‘alayhi wa sallam. You also bear no sin because of what you have mentioned, that your father shows those photos, so long as you are unable to prevent him or erase them; and Allaah never charges a soul with what is beyond its capacity, as He Says (what means): {And We charge no soul except [with that within] its capacity.}[Quran 23:62]
As long as you are unable to get rid of those photos, then, there is no sin on you because your father shows them. For further information, see Fataawa 86230 and 83259.
Dear sister, we advise you to strive in supplicating Allaah to guide your parents, and to do your best to invite them to Islam, for they are the most entitled to your dutifulness, supplication and sympathy. You should also be keen on adhering firmly to Islam, in order to be a mirror through which your parents would see the greatness of this religion.
Allaah Knows best.